Machine for the manufacture of stacks of slats for venetian blinds



H. P. PEETERS' Oct. 6, 1970 3,531,333

MACHINE FOR THE MANUFACTURE 0F STACKS 0F I SLATS FOR VENETIAN BLINDS 5 Sheets-Sheet 1 Filed Jan. 18, 1968 Oct. 6, 1970 H. L. P. PEETERS 3,531,333

MACHINE FOR THE MANUFACTURE OF STACKS OF SLATS FOR VENETIAN BLINDS Filed Jan. 18, 1968 5 Sheets-Sheet 3 FIG.3

Oct. 6, 1970 H. L. P. PEETERS 3,531,833

MACHINE FOR THE MANUFACTURE OF STACKS 0F SLATS FOR VENETIAN BLINDS Filed Jan. 18, 1968 5 sheet-sheet 4 FIG.7

Oct. 6, 1970 H. L. P. PEETERS 3 MACHINE FOR THE MANUFACTURE OF STACKS OF SLATS FOR VENETIAN BLINDS 1 Filed Jan. 18, 1968 5 Sheets-Sheet 5 United States atent U.S. Cl. 29-245 6 Claims ABSTRACT OF THE DISCLOSURE A machine for the automatic manufacture of Venetian blinds with the slats in stacked position whereby said machine requires minimum room and is very compact. The machine comprises a lifting device for the slats which are horizontally fed into the machine one by one, with a driving mechanism connected to said lifting device. The machine further comprises suspension and tensioning means for ladder tapes or ladder cords and may also comprise means for arranging the lift cords for the blinds.

This invention relates to a machine for the manufacture of stacks of slats for Venetian blinds, preferably of stacks of slats provided with carrier means, such as ladder tapes or ladder cords, lift tapes, lift cords or the like, and/or a head rail.

The invention aims at providing an automatically operating machine of this kind, which not only operates safely and efliciently but is also extraordinarily compact.

For this purpose the machine according to the invention is characterized in that the machine comprises among other things a lifting device into which the Venetian blind slats may be horizontally fed one by one, said lifting device being connected to a driving mechanism for periodically operating the lifting device and comprising among other things a number of lift units each provided with at least one lift member, said lift members being jointly movable in vertical direction alternately upwards and downwards for lifting each time a slat fed into the lift device to above the stops over a distance at least equal to the mutual distance of the cross connections, such as cross tapes or cross cords of the relative carrier means; suspension means and tensioning means for vertically providing, distributed in the longitudinal direction of the machine, the carrier means, such as ladder tapes or ladder cords, or keeping said carrier means tensioned in the vertical and transverse direction and guiding them respectively; guides for the slats and, if necessary, means for arranging the lift means during or after the assembling of the stack, all these parts being adjustable in the longitudinal direction of the machine.

An advantage of this machine is that, also if said machine is used for the manufacture of stacks of slats provided with ladder and/or lift means, the entire unit is directly manufactured in slat form and not in the form in which a Venetian blind is in lowered condition. Consequently the machine occupies only little space in the directions transverse to its longitudinal direction.

In the machine according to the invention the lifting device preferably consists among other things of a shaft adapted to be driven in two senses of rotation, said shaft extending in the longitudinal direction of the slats along the machine and carrying at the location of each lift unit a winding means adjustable in axial direction of the shaft, for example a pulley, to which there is fastened a tape, cord or the like adapted to be wound on said winding means, said tape, cord or the like carrying at its free end a lift member, such as a lift plate, said lift member being vertically movable relative to a guide frame and carrying at least one carrier means, such as a pin or the like, which in the lowermost position of the lift means projects below the feed path of the slats.

Another characteristic of the machine according to the invention is that the guides of the slats are mainly U-shaped and are arranged in front of and/or behind each lift unit, viewed in the direction of feed of the slats and the legs of the guides are provided with resilient stops for allowing the slats to pass and for carrying the slats afterwards.

The invention is furthermore characterized in that at the location of each lift unit below the slat feed path a ladder tape tensioning device is provided, consisting of a pair of ladder tape tensioning elements pivotally mounted at one side and co-operating at the other side with each other, said ladder tape tensioning elements being provided with slots for continuously guiding the side tapes of the ladder tape and keeping them apart, and of a central part for temporarily keeping each time a cross tape of the ladder tape under tension.

Still another characteristic of the invention is that at the location of each lift unit there is provided a ladder cord tensioning unit consisting among other things of at least two guiding means, for example rollers, provided with guides for guiding the side cords of the ladder cord and keeping them apart, and a preferably spring pressure biased tensioning means pivotal at one side, for example a plate, for temporarily keeping each time a cross cord of the ladder cord under tension.

It is of advantage if at least at the location of a number of lift units a threading needle is detachably provided, said threading needle projecting vertically in downward direction at the location of punched-out openings provided one above the other in the stack of slats, said threading needle comprising fastening means for a lift tape, a lift cord or the like for upwardly or downwardly threading the lift cords through the slats.

According to the invention the ladder cord tensioning unit is preferably fastened to a rocking element which is rockably or rotatably connected to a frame adapted to be adjusted and locked relative to the stationary frame of the machine in the longitudinal direction of the machine, said rocking element comprising means which cooperate with means of the lift member for rocking or pivoting the rocking element with the ladder cord tensioning unit alternately to the left and to the right during the successive upward movements of the lift means moving alternately upwards and downwards, in order to bring the cross cords of the ladder cord alternately to one side and to the other side of the threading needle.

The invention will be further explained below with reference to the drawings showing by way of example an embodiment of the machine according to the invention.

FIG. 1 presents a diagrammatical front view of the machine. a

FIG. 2 is a top plan view of the machine.

FIG. 3 is a front view of an embodiment of the guiding and ladder tape tensioning unit.

FIG. 4 shows the unit according to FIG. 3 in another position.

FIG. 5 shows a front view of an embodiment of the guiding and ladder cord tensioning unit.

FIG. 5a shows a detail.

FIG. 6 shows the unit according to FIG. 5 in another position.

FIG. 7 shows in perspective and on an enlarged scale a front view of the unit according to FIGS. 5 and 6 with removed guiding and ladder tensioning unit.

FIG. 8 shows a front view of part of the machine with another embodiment of the guiding and ladder cord tensioning unit, as well as with the lift cord threading unit.

FIG. 9 is a side view of the ladder cord tensioning unit according to FIG. 8.

The machine shown in the drawings comprises a frame 1 provided with supports 2, 3 with which the frame rests on the ground. The lifting device comprises a shaft 4 supported in bearings 5, 6 which by means of bearing bracket supports 7, 8 are secured to the frame 1.

At one end, to the right in FIGS. 1 and 2, the shaft 4 carries one half 9 of an electro-magnetic clutch 9, 10, the other half 10 of which is secured to the shaft of an electromotor 11 mounted on the frame 1. The shaft 4 furthermore carries, distributed over its length, a number of pulleys 12, said number amounting to four in the embodiment shown. The pulleys are slidable along the shaft 4 but they are mounted nonrotatably relative thereof in that the shaft 4 has a square cross-section and in the pulleys 12 a corresponding square central aperture is provided. The slidability is required in order to be able to change the position of means (to be described later on) for the provision of ladder means from which the slats are suspended.

Below each pulley 12 there is secured to the frame 1 a vertically extending guide plate 13 along which a lift plate 14 is vertically slidable. The lift plate 14 is connected with the pulley 12 by a tape 15 of spring steel one end of which is connected to the lift plate 14 and the other end to a point on the circumference of the pulley 12. The lift plate 14 carries two forwardly projecting pins 16 by means of which a slat 17, horizontally fed into the machine, is supported and remains thereon after the slat has been entirely fed into the machine. By a rotation of the shaft 4 in one sense the slat 17 is lifted.

This rotation is obtained as follows. On the shaft 4 there is fixedly arranged a cam disc 70 (FIG. 2) With which the lift of the lift plate 14 is defined. With the cam disc 70 there is associated a follower member in the form of a follower roller 73 connected to the switch arm of a micro switch 74. This switch 74 is included in the energizing circuit of the electro-magnetical clutch 9, 10. When the motor 11 is started and a slat 17 has been entirely fed into the machine, the slat Comes into contact with an end switch 75 which is likewise included in the energizing circuit of the clutch. The end switch 75 is operated by the slat 17 and causes the energisation of the clutch so that said clutch is let in and is connected to the shaft 4. When the follower roller 73, running on the cam disc 70, is actuated by the cam on said disc the switch 74 interrupts the supply of current to the clutch so that the shaft 4 is stopped. In consequence of the weight of the lift plates 14 depending from the pulleys 12 a torque is created acting on the shaft 4 which thereby moves it back into its initial position.

The guide plate 13 (FIGS. 3 and 4) Comprises at its top two upwardly projecting legs 18 extending on either side of the pulley 12. By means of an adjusting screw 13' the guide plate 13 may be adjusted along the frame 1, the pulley 12 being taken along by the legs 18.

On either side of the guide plate 13 there are arranged U-shaped guides 19 for the slats 17 beside the pins 16. The guides 19 are connected to the guide plate 13 and are adjusted together with the adjusting of the guide plate 13. The guides 19 have in the legs of the U at some distance above the bottom side resilient stops 20. If a slat is moved upwards by means of the shaft 4 up to the stops 20, then said stops are pushed inwards into the legs of the U and upon further movement and after the passing of the slat they spring back so that they can support said slat. Each following slat is likewise pressed beyond the stops 20 so that finally the entire stack of slats rests on the stops 20.

In order to provide ladder tape in the stack of slats simultaneously with the assembling of said stack it is preferred to arrange at each lift unit such a ladder tape 21 in such manner that the first slat of a stack, when being fed into the machine, is positioned between two cross tapes 22 situated near the end of the ladder tape 21. After a first slat has been moved through, the ladder tape 21 may be released and then depends substantially vertically from the uppermost cross tape 22. When the slat is lifted it also causes the ladder tape 21 to be lifted by means of said uppermost cross connection 22. The distance along which the lift is carried out, therefore the distance between the pins 16 and the stops 20, is at least equal to the distance between two successive cross connections 22 of the ladder tape 21. After a slat has been lifted the next slat is automatically pushed between two successive cross connections 22 etc.

In order to render this possible the ladder tape must be maintained under tension in the longitudinal direction and besides both side tapes must be kept apart in the transverse direction so that the slat cannot be hindered when being moved forwards. For this purpose each lift unit may be provided, in addition to the guide plate 13, the lift plate 14 and the guides 19, With a ladder tape tensioning means consisting of a pair of tensioning elements 24. The tensioning elements 24 are U-shaped and made from sheet metal. Near one end of each element 24 a pivot shaft 25 is arranged through the legs of the U- shaped element on which the element 24 is rotatably mounted and which shaft 25 is fixedly secured to the frame of the tensioning means. The legs of both elements 24 situated nearest to the frame 1 are each provided with a gear segment 26, both gear segments being in engagement with each other after the elements 24 have been mounted to the frame. One of the segments 26 is connected at some distance from the pivot shaft 25 to one end of a tensioning spring 27 the other end of which is secured to the frame of the tensioning means. Centrally relative to the unit there is provided at the lower side of the frame 1 a U-shaped guide 29 having two legs projecting from the frame 1, the ladder tape 21 depending between these legs. Each element 24 is provided with two slots 30 in the body of the U at the point Where the body and the legs of the U-shaped element meet, said slots extending parallel to the legs.

The above-described ladder tape tensioning means operates as follows.

In the initial position (FIG. 4) the elements 24 are in the horizontal position, the free ends thereof facing each other with a small clearance. In this situation each side tape of the ladder tape 21, depending from slats al ready supported by the stops 20, projects into two slots 30 of the elements 24, said slots facing each other. These elements are also shown in my co-pending application Ser. No. 698,932 filed Jan. 18, 1969. The elements 24 have been brought in this position by the tensioning spring 27 and by the cooperation of the gear segments 26, the limitation in downward direction being obtained for example by stops or by gearless ends of the gear segments. When the lift plate 14 is lifted the pins 16 move the slat resting thereon upwards, said slat exercising an upward pull on the ladder tape by means of the cross connection 22 situated above said slat. The side tapes may be moved upwards through the slots 30 of the elements 24. If a cross connection 22 situated below the elements 24 abuts against the bodies of said elements 24, then said bodies are taken along upwards and said elements move apart, against the action of the tensioning spring 27 and pivot about the shafts 25 so that said cross connection 22 may pass the body ends of the elements 24. However, the side tapes remain guided with their edges in the slots. Immediately after the cross connection has passed the elements 24 return to their initial position under the influence of the spring 27, in which position the bodies, under the influence of the spring 27 preferably exert a slight pressure on the next cross tape so that a tensioning of the ladder tape occurs in the transverse and in the longitudinal direction.

If the Venetian blind to be manufactured must be provided with ladder cord instead of ladder tape a ladder cord tensioning unit is provided instead of the ladder tape tensioning unit. A first embodiment thereof is shown in FIGS. 5 and 6.

This unit consists of a plate 31 carrying at the lower side a holder 33 fixedly connected therewith, in which two rollers 34, for example of synthetic material, are rotatably mounted by means of journals or shafts 35. The journals 35 of one of the rollers project into slotlike openings 36 in the holder 33, and the journals of the rollers are interconnected on either side of the holder by a tensioning spring 37, said springs urging the rollers towards each other. When the ladder cord 38 is situated between the rollers 34 and a pull is exercised thereon by lifting a slat, (corresponding with the situation in the case of a ladder tape), the springs 37 ensure the necessary longitudinal tension in the ladder cord 38. Keeping the d ladder cord open in the transverse direction is ensured by means of a spacer 39, consisting of a plate 41 pivotally connected about a shaft 40 to the plate 31, slots 42 being provided at the free end of said plate 41 for accommodating the side cords of the ladder cord 38. The spacer 39 is biased by a tensioning spring 43 towards a position approximately parallel to the plane through the center lines of the rollers 34, the free end of the plate 41 resting on a cross connection cord of the ladder cord 38. In the rollers 34 there are provided peripheral grooves for correctly guiding and spreading the side cords.

The operation of this ladder cord tensioning unit corresponds with the operation of the above-described ladder tape tensioning unit.

Another embodiment of the ladder cord tensioning unit is shown in FIGS. 8 and 9. In this case rollers 46 are mounted on a holder 47. These rollers are approximately barrel-shaped and comprise shoulders 48 at their ends so that the side cords of the ladder cord are automatically kept apart. Prior to passing across the rollers 46 the side cords each extend along one side of a flap 49 which is pivotally mounted about a shaft 50 at the under side of the holder 47 between two side plates 45. At one side of the flap 49 there are provided stops 51 on the inner sides of the side plates 45. The flap 49 is spring-biased such that it contacts the stops 51. The upper end of the flap 49 comprises sides tapering inwards relative to the holder 47, the flap fitting with these sides between the side cords of the ladder cord so that an uninterrupted guiding of the side cords in outward direction and thus a tensioning of the side cords in transverse direction is brought about and if necessary also the cross cords may be kept under tension. The cords pass around said sides of the flap 49 and thereafter below the stops 51, and subsequently across a fixed cross pin 52 of the holder 47 downwards. Thus the flap 49 can attend to the longitudinal tension in the ladder cord (through the spring) as well as to keeping the cord open. When a slat is lifted the flap 49 deflects against the spring tension so that consequently said flap 49 pivots away out of the path of the relative cross connection of the ladder cord and the latter therefore may pass. The holder 47 is fixedly secured to the plate 31.

From FIG. 8 it is apparent that the guide plate 13 of each lifting device carries a column 53 with a guide bar 54 along which a holder 55 is vertically slidable, said holder carrying at the lower side a vertical threading needle 56. The threading needle 56 has at its lower end an eyelet 57 through which a lift cord 58 may be threaded. At the location of the threading needle 56 the slats of the stack are provided with an aperture 59, said apertures forming a vertical channel in the stacked package. The threading needle 56 projects through this channel after the slats have been raised during their upward movement below the needle. When the required number of slats have been added to the stack one may thread the lift cord 58 through the openings in the slats by moving the holder 55 with the threading needle 56 upwards. The cord 58 with the needle 56 may also be threaded from an upward position downwards through the channel formed by the openings when during the assembling of the stack the needle is situated in a position above said stack or is situated at the location of the stack and the lift cord has been previously threaded in the needle.

In order to prevent the shifting of the slats in a completed Venetian blind at a possible inclined position of the blind or through other causes that the slats with their lift cords show a deflection as a consequence of being shifted relative to the carrier means, the lift cords of the ladder tape are threaded through slots in the center of the cross tapes which are mostly provided double or in zigzag fashion. In the case of ladder cord this is normally corrected by guiding the lift cord by hand alternately to the left and to the right. The invention also comprises a provision for automatically carrying out this weaving, which is explained with reference to FIGS. 5, 6 and 7. According to this arrangement care is taken that the lift cord is alternately situated to the left and to the right of the successive cross connections. This is obtained by a rocking movement of the ladder cord tensioning unit. This unit is secured to a plate 31 constructed as a rocking element, said plate being pivotally mounted about a journal 32 of a supporting plate 66, said supporting plate being secured to the frame 1. At the rear of the rocking element 31 a pin 60 is secured, and on the lift plate 14 a fixed guide 61 (FIG. 7) is provided consisting of a vertical slot downwardly widening into oppositely inclined portions 67 and underneath a triangular tipping guidepiece 62 adapted to tip about a pivot pin 63 situated near the top angle of the tipping guidepiece 62 and secured to the lift plate 14.

In order to explain the operation of this structure the lowest position of the lift plate 14 is selected as a starting point, in which position the pin 60 is situated in the top of the vertical slot of the fixed guide 61. It is thereby assumed that the tipping guidepiece 62 has been tipped to the right.

When the lift plate 14 is drawn upwards by the shaft 4 and the pulley 12 via the tape 15, a slat lying on the pins 16 is conveyed in upward direction, the upper side of the slat engaging the ladder cord. During this movement the slot of the fixed guide 61 moves upwards relative to the pin 60, just like the tipping guidepiece 62 which is in a position tipped to the right.

The tipping of the tipping guidepiece 62 is limited in that downwardly projecting parts abut against the stop 65 (FIG. 7). The tipping piece comes with its left erect side into contact with the pin '60 which consequently is pushed away towards the left. Upon the pin 60 being pushed towards the left also the ladder cord tensining unit and consequently the ladder tape are moved towards the left so that the next cross connection of this ladder cord assumes a position to the left of the threading needle 56 during the upwardly directed movement of said ladder cord relative to the threading needle.

Immediately after the pivot pin 63 has passed the pin 60, the tipping piece 62 is tipped to the left by the pressure exerted by the pin 60 on the lower part of the tipping piece, the left erect side assuming an almost vertical position. Meanwhile the relative cross connection of the ladder tape has passed the end of the threading needle to the left.

At the subsequent downward movement of the lift plate 14 under the influence of the force gravity the tipping piece moves along downward in the position turned to the left. This is effected at such a speed that the pin 60 does not get a chance to push back the portion of the tipping piece situated above the pivot pin 63. Consequently the tipping piece remains in the position turned to the left and the pin 60 comes into contact with the left inclined portion 67 of the fixed guide 61 so that at a continued downward movement of the lift plate 14 the pin "60 is automatically guided in the vertical slot.

At the subsequent transport of the next slat by the renewed upward movement of the lift plate 14 the right erect side of the tipping piece now comes into contact with the pin 60 so that this pin is pushed towards the right and the next cross connection of the ladder cord therefore assumes a position to the right of the threading needle.

In this way the successive cross connections may therefore be brought to the .left and to the right of the threading needle.

I claim:

1. A machine for the manufacture of stacks of slats for venetian blinds, the stacks comprising slats and ladder .means of the type having cross connections exactly overlying each other when the ladder means is in vertically stretched condition said machine comprising: a machine frame; a lifting device into which the venetian blind slats may be horizontally fed one at a time; a driving mechanism connected to said lifting device for periodically operating the lifting device, the lifting device comprising a number of lift units each provided with a lift member, said lift members being jointly movable in a vertical direction alternately upwards and downwards for successively lifting subsequent slats fed into the lift device over a distance at least equal to the distance between adjacent cross connections of the ladder means; tensioning and guide means adjacent the location of at least one of the lift units in the form of a ladder means tensioning unit; threading means located adjacent at least one of said lift units, the threading means comprising a detachably mounted threading device projecting vertically downward and having means for threading the lift means through lift means holes in the slats during or after the assembling of the stack; said ladder means tensioning unit being attached to a rocking element movably connected to a frame which is adapted to be adjusted and locked relative to the stationary frame of the machine said rocking element comprising contact means which co-operate with part of the lift member to move the rocking element along with the ladder means tensioning unit alternately to the left and to the right during the successive upward movements of the lift means in order to bring the cross connections of the ladder means alternately to one side and to the other side of the threading device.

2. A machine according to claim 1 wherein the lifting device comprises a shaft adapted to be rotated in two senses of rotation, said shaft extending in the longitudinal direction of the slats along the machine and carrying-at the location'of each lift unit a winding means adjustable in axial direction of the shaft to which there is fastened a drawing means adapted to be wound on said winding means, said drawing means carrying at its free end the lift member said lift member being vertically movable relative to a guide frame and carrying a carrier means for lifting the slats, the carrier means projecting in the lowermost position of the lift member below the feed path of the slats.

3. A machine according to claim 1 wherein said contact means of the rocking element is a follower member projecting from the rocking element, and the part of the lift member comprises a fixed guide with oppositely directed oblique or curved portions having below it a substantially triangular tipping guidepiece which near its upwardly pointing angle is pivotally connected to the lift member.

4. A machine according to claim 1 wherein the ladder means tensioning unit comprises guiding means provided with guides for guiding the sideparts of the ladder means and keeping them apart, and a tensioning element pivotally arranged for temporarily exerting a vertically downward tension force on a cross connection of the ladder means.

5. A machine according to claim 4 wherein the tensioning element is plate-shaped and is spring biased and pivotally secured near one end and includes two extra guides for the ladder means constituting stops for limiting the movement of the free end of the plate-shaped tensioning element co-operating with the cross connections.

6. A machine according to claim 1 wherein the machine is provided with a number of frame structures which are movable and lockable relative to the stationary longitudinal frame of the machine, also including a lift unit, a ladder means tensioning unit, and threading means secured to each of said frame structures.

References Cited UNITED STATES PATENTS 2,893,106 7/ 1959 Rosenbaum 29-245 3,292,232 12/1966 Nilsson 2924.5

JOHN F. CAMPBELL, Primary Examiner R. I. CRAIG, Assistant Examiner US. Cl. X.R. 2933, 200 

